Many implantable medical devices include a connector bore with which a connector terminal of an implantable medical electrical lead may mate, via insertion therein, in order to electrically couple electrodes, and/or other active sensing or therapy delivery members of the lead, with power and control circuitry contained in the device. The typical implantable medical electrical lead includes an elongate insulative body within which insulated conductors extend, wherein the conductors couple sensing or therapy delivery members, mounted on the lead body, to contact members of the connector terminal. Each contact member of the lead connector terminal electrically engages with a corresponding device contact within the device connector bore when the lead connector terminal is fully inserted therein.
Numerous configurations of implantable medical electrical lead connector terminals have been disclosed over the years, many of which are directed toward compliance with international industry standards that specify essential dimensions and performance requirements to assure compatibility of connection between device connector bores and lead connector terminals among a variety of manufacturers. The most recently developed international standard, ISO/FDIS 27186:2009(E), dictates the form for a four-pole in-line connector terminal of cardiac pacing and defibrillation leads and is commonly known as the IS-4 (or DF-4) standard. Commonly-assigned U.S. Pat. Nos. 7,108,549 and 7,241,180 disclose lead connector terminal embodiments that may comply with the IS-4 standard. Although these disclosures, as well as others, define various configurations and arrangements of structural elements and electrical connections that accommodate the construction of an implantable medical electrical lead with an integral multi-pole in-line connector terminal, there is still a need for improved designs and associated assembly methods.